This invention relates generally to the uncoupling of a trailer from a tractor vehicle and relates more particularly to the release of a king pin from a fifth wheel coupling mechanism used to couple a trailer to an over-the-road tractor vehicle.
The class of king pin coupling mechanisms with which this invention is concerned includes a handle which must be moved between two positions of movement in order to release the king pin from the coupling mechanism. Commonly, the handle is moved in a substantially linear direction as it is moved from a lock position at which the king pin is captured by the coupling mechanism and a release position at which the king pin is released from the coupling mechanism. Examples of known coupling mechanisms having such a handle are shown and described in U.S. Pat. Nos. 4,592,566, 2,885,222, 4,871,182 and 4,106,793.
To uncouple a trailer from a tractor vehicle, the handle of the coupling mechanism is grasped by a user and pulled upon in order to release the king pin from the coupling mechanism. By pulling upon the handle with sufficient effort, the handle is moved from its lock position to its release position. If the coupling mechanism includes a safety catch which prevents the handle from being inadvertently moved out of its lock position, the safety catch must be appropriately displaced by the operator to an out-of-the-way position before the handle can be moved to its release position. In either event, the operator must reach into the space provided between the bottom of the trailer frame and the drive wheels of the tractor in order to manipulate the handle and/or the safety catch. Normally, the space between the trailer frame and tractor tires within which the operator must reach is cramped rendering manipulation of the handle and/or safety catch difficult. Moreover, the positioning of an operator's arms between the trailer and tractor exposes the arms to the danger involved in an unintentional separation of the trailer from the tractor vehicle.
Accordingly, it is an object of the present invention to provide a new and improved tool which facilitates the release of a king pin from a fifth wheel coupling mechanism of the aforementioned class.
Another object of the present invention is to provide such a tool which eliminates the need for an operator to reach between the trailer and tractor tires in order to release the king pin from the coupling mechanism.
Still another object of the present invention is to provide such a tool which enhances the safety of an operation involving the uncoupling of a trailer from a tractor vehicle.
A further object of the present invention is to provide such a tool which is uncomplicated in construction and effective in operation.